Explain the Term Disproportionation Reaction

Answer: In chemistry, disproportionation is a reaction in which a chemical reactant, such as a compound, is simultaneously oxidized and reduced. 

It is a reaction that can occur both in series and concurrently. Disproportionation reactions can be catalyzed or are otherwise difficult to perform. These reactions can take place in a natural, catalytic, or artificial setting.

Disproportionation reactions are a special case of redox reactions. The oxidant is reduced by the reductant in the disproportionation processes, while the reductant is reduced by the oxidant.

Following are some examples of disproportionation reactions to make you understand the term more precisely:

1. Decomposition of hydrogen peroxide(H₂O₂)

The significantly less stable H₂O₂ dissociates to create more stable H₂O and O₂.

2H₂O₂→2H₂O+O₂

In the compound H₂O₂, the oxidation state of the oxygen atom is -1. This oxygen atom gets reduced to H₂O, where its oxidation state becomes -2. The same oxygen atom also gets oxidized to O₂, gaining the oxidation state 0, thus getting both oxidized and reduced simultaneously.

2.Dissociation of hypochlorous acid (HOCl)

Hydrochloric acid (HCl) and chloric acid are formed when HOCl is broken down (HClO₃).

3HOCl→2HCl+HClO₃

The chlorine atom in HOCl has an oxidation state of +1, which is oxidized to HClO₃, which has an oxidation state of +5. The same chlorine atom is reduced to HCl as well, resulting in an oxidation state of -1.

3.Reaction of nitrogen dioxide (NO₂) and water (H₂O)

Nitric (HNO₃) and nitrous (HNO₂) acids are formed when NO₂ interacts with water.

2NO₂+H₂OHNO₃+HNO₂

NO₂ has a +4 oxidation state for nitrogen. It is oxidized to HNO₃, which has a nitrogen oxidation state of +5. It’s also reduced to HNO₂, giving it an oxidation state of +3.

In the above examples, oxygen, chlorine, and nitrogen are simultaneously getting oxidized and reduced respectively which shows these reactions are disproportionation reactions.